From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: Display of undisplayable characters: \U01F3A8 instead of diamond Date: Sat, 03 Sep 2022 09:44:46 +0300 Message-ID: <83mtbhneht.fsf@gnu.org> References: <87edx28cl1.fsf@disroot.org> <83y1v7w6eu.fsf@gnu.org> <2f302d1c3966849477b3@heytings.org> <83mtbiovzr.fsf@gnu.org> <83a67hq3l7.fsf@gnu.org> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="22025"; mail-complaints-to="usenet@ciao.gmane.io" Cc: acm@muc.de, gregory@heytings.org, emacs-devel@gnu.org To: rms@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sat Sep 03 08:49:02 2022 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1oUMxi-0005bW-3g for ged-emacs-devel@m.gmane-mx.org; Sat, 03 Sep 2022 08:49:02 +0200 Original-Received: from localhost ([::1]:48786 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oUMxh-0006fj-54 for ged-emacs-devel@m.gmane-mx.org; Sat, 03 Sep 2022 02:49:01 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:59226) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oUMu7-0005D2-Vi for emacs-devel@gnu.org; Sat, 03 Sep 2022 02:45:19 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:57324) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oUMu7-0002aj-HR; Sat, 03 Sep 2022 02:45:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=UaQZe61aDy57hJafFA3lXKtxKZDcOmuO8/wWpAwqIZk=; b=qGx5LXcKbz59 /YQuTrMc15gEFhgTBujqn8nb/0I7LGVyR79OgtyfBtn3uKx6NmC62ovW7YjKbjIlg9yWq5VUY1m4j 2j2gmjqKvFG0QgnTD+a4NHVADyDRNL4Q00Jd5G6jcWeGLA6CcK3mL1/WJz2Op13ezl1L1gZEFZTVs YcSqWRXJFDIgOPwrshYNdBmipzvmyR6xD/NJBKUQ2TTjr2YlFY+OGlJn+CEHl5bt3BAwJxTS3zwAV yt+M8PJ6lHgI9FQBoso0qNClnUt0Enpy7JTRVvmJaoN20DLjzVh1ITaDQ4LJ+zWqUyjVwpDkQouS0 hYDzOx6vila31BrsAJPrqA==; Original-Received: from [87.69.77.57] (port=3606 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oUMu2-0002ah-BL; Sat, 03 Sep 2022 02:45:14 -0400 In-Reply-To: (message from Richard Stallman on Fri, 02 Sep 2022 22:51:27 -0400) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:294611 Archived-At: > From: Richard Stallman > Cc: acm@muc.de, gregory@heytings.org, emacs-devel@gnu.org > Date: Fri, 02 Sep 2022 22:51:27 -0400 > > > How can Emacs know which characters does your Linux console actually > > support, out of all the Unicode range? > > A few days ago you said it could use char-displayable-p > to determine this. If that works, it solves the problem of finding out > which characters to display as diamond. It works, but looping over all the Unicode characters is very slow, so doing that at each startup would be unacceptable. If someone needs, I can show a simple code to be run by the user, once, on the Linux console, that would allow then to determine the codepoint ranges for which the U+FFFD (or any other) replacements are needed, so that users could run that code, and then put such customizations in their init files. We could even have a special command to do that, if people think it's important and helpful. But all I hear till now is flat rejection of that solution, which is a very weak incentive (to say the least) to work on such a command. > As for how, it would be asy to add a variable whose value should be a > vector containing integers, or a single-byte string, saying what to > send. This will be adequate for a Linux console, and it doesn't need > to handle anything else. You are describing what display-tables provide. That's the solution I recommend if you really want to see those U+FFFD "diamonds" instead of the characters that cannot be displayed. I see no reason for yet another solution for a problem for which we already have two (glyphless-char-display and display-tables).